Therapeutic lamp



y 1935- R. H. MAXSON 2,006,402

THERAPEUTIC LAMP Filed July 17, 1931 3 Sheets-Sheet 2 July 2, 1935. R. H. MAXSON 2,006,402

THERAPEUTIC LAMP Filed July 17, 19551 '3 Sheets-Sheet 5 @MM WWI/$14.3

Patented July 2, 1935 PATENT OFFICE THERAPEUTIC LAMP Rolland H. Maxson, Milton, Wis., assignor to The Burdick Corporation, Milton, Wis., a corporation of Delaware Application July 17, 1931, Serial No. 551,321

8 Claims.

My invention relates to therapeutic lamps.

It will be illustrated and explained as embodied in a lamp of the mercury arc tube type wherein air circulation is depended upon to dissipate the heat generated by the arc. Such lamps, usually known as the air cooled type, are particularly useful for generalized application of ultra violet rays to the patients body, asdistinguished from localized treatments. They have been extensively used for a considerable number of years but heretofore have exhibited a rather troublesome defect; viz., too great a dispersion and consequent thin spread and loss of effective rays. Reflectors have been provided to lessen the dispersion and loss but yet much of the light generated has been scattered far beyond the field of use (i. e., the patients body) lengthening the time of treatment and creating a troublesome hazard to attendants and others not undergoing treatment. Heretofore, attempts satisfactorily to lessen dispersion have only brought about other diillculties,such as the inability to dissipate the heat generated by the tube or burner at a rate sufficient to prevent overheating and resultant uncertainty of operation. In addition, the methods of mounting the tubes in the reflectors have been such that the relatively frail quartz envelopes have been subjected to strains with the result that breakage has been rather excessive.

One of the objects of my invention is to provide a therapeutic lamp of the general application type which is more effective and reliable than those heretofore used.

Another object is tolessen dispersion and lost or ineffective rays.

Another object is to provide more effective ventilation and cooling for lamps of the aircooled reflector type.

A further object is to improve the tube mounting within the reflector.

Other objects and advantages of my invention will hereinafter appear.

An embodiment of my invention is illustrated in the accompanying drawings, wherein Fig. 1 is a bottom plan of the casing and reflector, with the doors open to show therein the tube and its mounting;

Fig. 2 is a section on the line 2-2 of Fig. 1; and

Fig. 3 is a section on the line 3-4 of Fig. 1.

In general, the therapeutic lamp embodying my invention comprises an outer semi-tubular (approximately semi-cylindrical) metal casing A, an elongated curved reflector B within the eas- 55 ing, a quartz mercury arc tube C, a tube support or mounting carried by the reflector and ventilating openings in the casing and reflector which cause the production of cooling currents of air to flow around and past the tube, to dissipate the generated heat at a rate to maintain the tube at 5 proper operating temperature. The tube mounting is such that, although the tube is accurately positioned and retained at the focal axis of the reflector, it is not rigidly clamped in position but is capable of such expansion and construction as 10 to relieve the relatively frail quartz envelope from injurious strains.

The outer casing A is formed from a sheet of metal bent into a substantially semi-cylindrical shaped body 5. The ends of the casing body are closed by a pair of semi-circular sheet metal heads 6,which may be slightlyoutwardlycrowned, as best illustrated in Figs. 1 and 2, to increase the rigidity and improve the appearance. Preferably I provide the bottom open side of the casing body with means for closing the casing to protect the tube and easily to regulate the time of treatments. The closure I prefer is in the form of two sheet metal doors 1. These doors are hinged along opposite longitudinal edges of the casing body by being attached to rods 8 which are journalled in small brackets 9 bolted tothe body adjacent the edges. Each rod 8 is provided with a knurled knob ill to facilitate the operation of the doors by the attendant or patient. Since the doors are, in effect, hinged somewhat above or back of the respective longitudinal edges of the casing body they are formed with a longitudinal bead or groove ii so that they may be closed without interference with the casing body. A spool l2, containing a flexible measuring tape i3 may be mounted on one head of the casing to facilitate the proper spacing between the lamp and a patient.

The rear curved surface of casing body 5 is provided, in its median region, with three groups of openings l4, l5 and it covered by louvers i1, i8 and I9 respectively for a purpose which will be presently explained. The body is also provided with a mounting bracket 20, only a portion of 5 which is shown in section in Fig. 3, and with a suitable electrical connector receptacle 2i whereby the lamp may be connected to a source of current by an ordinary plug and cord.

Reflector B comprises a sheet of metal bent into a trough-like body 25 of substantially hyperbolic cross section, as clearly shown in Fig. 3. Its inner surface is highly polished. The ends of the trough body are partly closed by heads 26 of substantially hyperbolic shape to hold the reflector to its proper curvature. Each head has an outwardly projecting flange 21 by means of which the head and the reflector body are anchored to the outer casing. This anchorage is effected by means of four small brackets 28 which are welded to the inner walls of easing heads 6 and to which brackets the flanges 21 are secured by screws 29. The interconnection between the end and flange portions of each reflector head is formed into a recess 30 (see Fig. 2) to receive a flexible metallic clamping band or strap 3| which encircles the reflector body adjacent each end and, by means of tensioning nuts 32, (see Fig. 3) tightly unites the reflector body to its two heads. The ends of reflector heads 25 are provided with large triangular openings 33 while the flanges are. provided with a series of slots 34 for a purpose to be hereinafter explained.

The tube or burner C for generating the ultra violet rays comprises a quartz envelope 4!) of generally L shape having a solid metallic anode 4| in the stem of the tube and a mercury cathode which, when the lamp is in operation, is more or less housed in the bowl 42 of the tube. The anode is connected to a metallic guard or shell 43 which encircles the end of the stem of the envelope while contact is made with the mercury cathode through an electrode immersed therein and connected to a terminal wire 44. A screw tightened but removable clamp ring 45 tightly encircles the anode guard 43 and carries the opposite terminal wire 46. The tube terminal wires 44 and 46 lead respectively to cathode and anode binding posts 41 and 48. These binding posts are carried by and project through the reflector, being suitably insulated therefrom. Wires from the rear of the binding posts lead, between thereflector and outer casing, to the external plug receptacle 2|.

The mounting for the tube comprises a pair of brackets which are carried by the reflector and engage the tube near its anode and cathode ends. The anode bracket comprises a small curved plate 50, which is anchored to the rear of the reflector body by screws 5|, and an extension plate 52 which projects through a relatively large opening 53 in the reflector body from the back to the front of the reflector. Bracket plates 50 and 52 are electrically insulated from each other by suitable sheets of approved insulating material, such as fiber, and secured together by screws 54; and plate 52 is provided with a circular opening or socket loosely to fit about the metallic anode guard 43. The insulation is required because the guard forms a part of the electrical circuit and it is desirable to insulate that circuit from the casing and reflector. The cathode bracket comprises a substantially Z shaped member 55 which is secured to the rear of the reflector body by screws 56 and projects from the back to the front thereof through a relatively large opening 51. This member is provided with a pair of spring clips 58 adapted resiliently to partly embrace the sides of the cathode bowl of the tube and a resilient foot 59 adapted to form a supporting and positioning seat for the bowl. Since the cathode bracket engages only the quartz envelope of the tube, which is an insulator, no extra insulation need be interposed between this bracket and the reflector.

The tube mounting brackets, and the reflector are so related that, when in position, the tube or burner'is located approximately on the focal axis of the reflector. Tubes may be removed and replaced very easily. Removal is effected by disconnecting wires 44 and 46 from binding posts 41 and 48 and then sliding the tube through the socket opening in the anode bracket until the bowl is released from the clips of the cathode bracket. Replacement is effected by reversing the procedure.

Locating the tube approximately on the focal axis of a deep reflector of substantially hyperbolic cross section increases the angle, of utilization (i. e. the angle within or by which the rays from the burner are reflected) and consequently reduces dispersion so that a relatively narrow band (wide enough to embrace a patientP-say about two feet wide) of relativelyintense ultra violet light may be produced. And the system of ventilating openings heretofore described affords sufficient cooling to permit the tube being so located with out danger of overheating. In other words I have provided a deep reflector of short focal length and located the burner near the apex, approximately on the line of the focal axis, and, in addition, I have provided a burner mounting and system of air cooling or ventilation whereby a mercury arc burner so located in relatively closely confining walls is not subject to overheating. Air circulates freely through the openings in the reflector supporting brackets at the front of the casing, up between the casing and reflector and out through the openings and louvers at the apex or top of the casing. These currents cool the reflector and the outer casing. Air also circulates into the open front or bottom of the reflector up and out through the large openings just back of the tube anode and cathode and out of the casing at the louvers. These currents of air cool the tube particularly in the regions of the anode and cathode so that the temperature does not rise sufficiently high to interfere with proper operation. Air also flows into the open front of the reflector, through the openings in the reflector heads into the space between the casing and the reflector and out the louvers. The air currents flowing between the casing and reflector not only serve to cool these parts but probably also assist in inducing the flow of air past the tube and its electrodes to keep them from attaining too high temperatures. A series of long openings 60 in the reflector body immediately back of the tube location may be found effective to insure the desired degree of cooling. None of these openings so located materially afiects the efliciency of the reflector. The large openings back of the tube electrodes causes very little loss of reflected light because little light is emitted in the regions of the electrodes. The narrow slots back of the stem of the tube cause little if any loss because, being narrow and in the median plane of the focal line of the reflector, whatever rays would strike these small areas would, even if the areas were reflecting surfaces, be reflected directly back into the burner and thereby lost anyway. The louvers covering the casing ventilating openings do not interfere with air circulation but do effectively prevent the escape of stray rays of light.

The burner supports very accurately position the burner or tube in the correct location and support the tube in such a way as to avoid strains. At the cathode end the bowl of the tube rests on a resilient seat while the sides are engaged by resilient clamps. Thus the tube is shielded from shocks and jars and strains from the expansion and contraction of the envelope. Like conditions obtain at the anode where the stern of the tube fits loosely a socket in a resilient bracket. Nor

does expansion and contraction of the reflector or casing subiect'the tube to strains.

Having thus illustrated and described the nature and an embodiment of my invention what I claim and desire to secure by U ted States Letters Patent is as follows:

1. A therapeutic lamp comprising an outer casing of generally semi-cylindrical shape, an elongated reflector of generally hyperbolic cross section mounted in and carried by the casing and having a pair of spaced ventilating op ning therethrough in the region of the apex of its curve, a pair of spaced supports carried by the therethrough,

with its electrodes in through the reflector whereby the electrodes are subjected to concentrated currents of air to cool the same to a greater extent than the mid-region of the tube.

2. A therapeutic lamp housing comprising a generally semi-cylindrical outer casing having ventilating openings in the median region-thereof, heads closing opposite ends of the casing, an elongated curved reflector supported within and by the casing and having spaced ventilating openings in the median region thereof, and lamp tube supports secured to the reflector and projecting from the rear toward the focal axis thereof in front of the ventilating openings therethrough.

3. A therapeutic lamp housing comprising an elongated curved reflector openings in its median region, opposite ends of the reflector, said flanges having ventilating openings therein, a generally semitubular outer casing having ventilating openings therein, brackets carried by the casing on the inner side thereof to receive the flanges of the reflector heads and thereby support the reflector within and spaced from the g, and a lamp tube support mounted on the reflector and extending in front of one of the openings thereof.

4. A therapeutic lamp housing comprising ah elongated curved reflector of generally hyperbolic transverse cross section and having a pair of axially spaced ventilating openings in its median region, a. pair of lamp tube mounting brackets attached to the rear side of the reflector and extending through the openings thereof to hold a lamp tube approximately at the focal axis of the reflector, and a semi-tubular outer casing enclosing and supporting the reflector at a distance therefrom so as to provide a ventilating space therebetween, said casing having a ventilating opening therein for the escape of air flowing through the ventilating openings of the reflector.

5. A therapeutic lamp'housing comprising an elongated curved reflector of generally hyp rbolic transverse cross section and having a pair of longitudinally spaced ventilating opening in its median region, a pair of lamp tube supporting brackets carried by the reflector and projecting from the front to the rear thereof through the ventilating openings therein, said brackets being provided with lamp" tube holders to support a lamp tube approximately along the focal axis of the reflector, lamp tube conductor terminals carried by the reflector, a semi-tubular outer casing with closed ends enclosing the reflector and provided with a ventilating opening therethrough in its median region to permit the escape of air flowing through the ventilating openings in the reflector, and means for anchoring the reflector within and spaced from the outer casing.

6. A therapeutic lamp comprising a semitubular outer casing having a luvered ventilating opening, an elongated reflector of generally hyperbolic transverse cross section carried by and series of ventilating openings in its median region, a pair of lamp tube supporting brackets spaced longitudinally of the reflector and carried thereby, and a lamp tube carried by the brackets on the focal axis of the reflector and with its electrodes located in front of the ventilating openings therein.

7. A therapeutic lamp comprising a semitubular outer casing having closed ends, a ventilating opening in its median region, an elongated reflector of substantially hyp rbolic transverse cross section and with a plurality of ventilating openings in its median region, means for mounting the reflector to and within the casing, a pair of brackets attached to the reflector and for holding a lamp tube in front of the reflector ventilating openings, one of the brackets having a series other bracket having a seat for loosely encircling another part of a lamp tube, and a lamp tube carried by the brackets at the focal axis of the reflector.

8. A therapeutic lamp comprising a reflector of generally hyperbolic shape but narrowed and deepened at its back to form an apex, a mercury arc tube disposed within the reflector adjacent the narrowed apex and'at substantially its focus, openings in the apex of the reflector opposite the ends of the tube, and brackets secured to the outside of the reflector and extending throu h the holes therein for supporting the respective ends of the tube.

ROLLAND I-l. MAISON. 

